1. Field of the Invention
The present invention relates to the methods and devices of a multi-functional operating interface for a care-taking machine.
2. Description of the Prior Art
Operation interface is a component indispensable and important to care-taking machines. What's more, the operational maneuverability of an interface affects the interaction between the user and the machine to every extent. By definition, the term care-taking machine used in this document refers to any kind of equipment that takes care of people and their lives, including electric wheelchair, living assistance and homecare equipment, computer interface, care-taking robots, etc., whose user can be the mentally or physically handicapped, children, the aged people, or even healthy people of all ages.
At the present stage, operation interfaces of care-taking machines generally fall into several categories by their means of giving commands: mechanical switch, operation stick, and body signal interface. The mechanical switches, including push button, breath switch, and touch button, offer only “on/off” operation mode. Due to its monotonous mode, the mechanical switch can offer only “yes/no” choice rather than complex options that must be standard for a care-taking machine such as an electric wheelchair. However, as such switches are easy to use and can be mounted on anywhere within a user's reach, they are often used for severely handicapped people.
Operation stick can provide some degrees of freedom of operation, so they are often used in an electric wheelchair or used as a computer interface. However, owing to its limited maneuverability, it is still inadequate for a sophisticated multi-functional care-taking machine that requires complicated operation system.
To tackle the above problem, the conventional solutions involve incorporating a combination of various operation interfaces, with each interface being responsible for a certain group of functions. This of course means that not only the functions that can be operated by severely handicapped people are significantly limited, but that even for the slightly handicapped, these systems are too complicate to operate.
The principle that underlies body signal type interfaces is by using sensing/detecting devices to obtain body signals reflected by the user (of a care-taking machine), which the system can analyze to determine the command to be given to the machine. The body signals used in the body signal type interface generally include: eye movement, brainwave (or electroencephalographic, EEG), electromyographic (EMG), and facial expression, etc. The eye movement signals are those signals and features of the movement of the eyeball, and the methods for collecting the eye movement signal include: Reflected Light, Electric Skin Potential, and Contact Lenses. This type interface can be used to control a care-taking machine with two or three degrees of freedom of operation, and its scope of use is roughly the same as that of the operation stick interface. However, it is mainly used for people who cannot move their hands.
Brain wave devices use electrodes attached on the scalp of a patient to detect the potential of his brain activities, which are further analyzed in order to perform the control activities thereby. Generally, the intensity of brainwave (or EEG) on the surface of the scalp ranges from 0 to 300 μV. For ease of understanding, EEGs are often divided into several sub-spectrums according to frequency: αwave (8˜13 Hz), βwave (14˜50 Hz), θwave (4˜7 Hz), and δwave (less than 3.5 Hz). EEGs are most often used to analyze a patient's brainwave activity. If used in control devices, various stimulations must be used to obtain changes in α, β, θ and δwaves so that commands can be given. As such, the types of stimulations chosen are often determined by the modes of control to be used. Currently, the majority of such interfaces used in care-taking equipment make use of audio and video stimulations, such as the brain wave's response to stimulation signals is often slow, stimulations have to be maintained all the time. Besides, these interfaces offer only limited degree of freedom of operation. Similar to the eye movement interfaces, the EEG interfaces are mainly designed to be used by the person whose body movement is disabled.
The principle of EMG interfaces is that electrodes are attached to the skin to detect the electric potential of muscle activity, which is further analyzed to perform the control activity thereby. The frequency of a stronger EMG signal can reach 3000 Hz, with an intensity ranging from 0 to 2000 μV. EMG is mostly used to analyze a recipient's muscle actions and the muscle's ability to respond to stimulations. Used in operation interfaces, it has to be worked through a couple of electrodes, performed through the setting and detection of a threshold voltage, which together offers multi-degrees of freedom of motion and multi-task control of a care-taking machine. As is described, in order for the system to work, the user has to apply quite a number of electrodes on his body, causing much inconvenience and discomfort. Besides, EMG interfaces have to make allowances for false actions caused by inadequate/improper positioning of electrodes. Further, the recipient's skin has to be cleaned before applying electrodes—a quite troublesome and uncomfortable procedure.
Facial expression interfaces use Charge Coupled Device (CCD) camera to record the recipient's facial expressions, and the images are stored and classified and compared with those in an established database by means of an image-process method in order to determine what commands to be given. Through the use of such a control interface, a user can use various facial expressions to control a multi-functional care-taking machine having multi-degrees of freedom of motion. However, as image-processing techniques are at the core of these systems, the number of images to be stored and analyzed must be limited to gain immediate control of the machine. As a result, mistakes and wrong actions often occur, substantially limiting its freedom of control.
The following is a table summarizing the features of control interfaces used by prior art care-taking machines:
TABLE 1CONTROL INTERFACES USED BY THE CONVENTIONAL CARETAKING MACHINESbody signalsmech.eyebrainfacialswitchesjoysticksmovementwavesEMGsexpressionsfreedom oflowlowlowlowmediumhighcontroluserhighmedium/highhighhigh/mediumhigh/disabilitylowmediumtechniqueson/offmulti-reflectionspectrummagnitude ofimageuseddirectionalskin potentialanalysissignalsprocessingon/offcontact lensthresholdvoltageinstanthighhighmediummediummediumlowcontrollabilityrisk oflowlowlowhighmediummediummistakesspecialnonodepending onspecial treatmentspecialNoPretreatmentmethods ofmust apply totreatment mustdetectionwhere the detectorsapplied toare attached,where theand stimulationsdetectors aremust be used toattachedobtain desiredresults